The Tower of Voices is a monumental 93-foot-tall musical instrument located at the entrance of the Flight 93 National Memorial in Shanksville, Pennsylvania. It was constructed as a living tribute to the 40 passengers and crew members who perished on September 11, 2001. The structure contains 40 uniquely pitched wind chimes, each representing one of the individuals on board. These chimes are activated by the wind, creating a "chorus" of varied frequencies that symbolize the voices of the heroes. The tower’s height (93 feet) is a direct reference to the flight number. Architecturally, it is designed with C-shaped concrete "clamshells" to optimize wind flow and resonate the sound throughout the surrounding meadow. It serves as a landmark feature that provides a sensory, auditory experience for visitors entering the memorial grounds, ensuring the memory of the forty is heard through the natural elements.